Extreme pressure lubricants



United States Patent EXTREME PRESSURE LUBRICANTS Helen Sellei Beretvas,Chicago, 111., assignor to Standard Oil Company, Chicago, 111., acorporation of Indiana No Drawing. Application June 28, 1954 Serial No.439,869

Claims. (Cl. 252-37.2)

This invention relates to improved extreme pressure lubricants and themethod of preparing same. It is particularly concerned with improvementsin such lubricants containing lead naphthenate, a sulfurized organiccompound and a chlorinated organic compound.

Extreme pressure lubricants containing lead, sulfur and chlorine arewell known to those skilled in the art and considerable research hasbeen conducted for the purpose of improving the load-bearing propertiesas Well as other extreme pressure characteristics of such lubricants.Such research has primarily been directed to the discovery of new sulfurand/or chlorine containing compounds which would yield their chlorineand sulfur more readily and thereby exhibit improved extreme pressurecharacteristics. Despite the large sums expended on research and thevast amount of time involved in investigating the effectiveness of themany sulfur and/or chlorine organic compounds, however, the .art has notdiscovered any truly outstanding additives of this type which are widelyaccepted over the many analogous compounds. Consequently, it has longbeen felt that a desirable approach to the problem might be an additivewhich would increase the etfectiveness of lead, sulfur, and chlorinecontaining lubricants and which would be generally applicable to thewide range of different sulfur and chlorine containing additivesemployed. It has now been found that the properties of sulfur andchlorine containing E.P. additives (extreme pressure additives) can begreatly enhanced and the overall effectiveness of lubricants containinglead naphthenate along with sulfur and chlorine containing E.P.constituents improved to a large extent by the addition of a minoramount of oleic acid.

In accordance with the present invention, lubricants comprising amineral lubricating oil in the higher vis cosity range, ordinarilyemployed in lubricants of this type, e.g. from about 45 to about 180S.S.U. at 210 F. and preferably from about 75 to about 110 S.S.U. at 210F., and containing a lead naphthenate, one or more organic sulfurcontaining EP. agent and an effective amount of a chlorine containingE.P. agent may be rendered more effective by combining therewithanamount of oleic acid of from about 1 to about and preferably from about2 to about 7%. Such lubricants may, of course, also contain efiectivequantities of various other typical lubricant additives such asantioxidants, detergents, etc. It should be understood that thelubricants of the type discussed herein are those useful principally inthe automotive use, e.g. in the hypoid gear of rear axles, etc., asopposed to the socalled extreme pressure or, more properly, extremetemperature lubricants employed in steel mill rolling operations, etc.The latter type of lubricant ordinarily contains viscous hydrocarbonoils such as asphalts or residuums and is a quite different type ofproduct generally unsuited to the requirements of automotive or likeuse.

The amount of lead naphthenate employed in extreme pressure lubricantsof the present invention may vary over a relatively wide range dependingupon a variety of factors, e.g. the end use of the lubricant, thelubricatr6 ICC ing oil employed, the sulfur :and, chlorine content, etc.

In any event, oleic acid has been found to improve the properties oflead soap containing extreme pressure lubricants having as little asabout'.1.'5% of lead naph- 5 thenate containing between about 25 and 30%lead.

The oleic acid is, however, useful in lubricants containingsubstantially greater amounts of lead naphthenate, e.g. as much as 10%of such a soap, and even higher resulting in lead contents-as high asabout 3% and higher.

In order to demonstrate thelimprovement obtained when employing oleicacid in lead, sulfur and chlorine containing extreme pressure lubricantsof the type herein described, data are set forth below which wereobtained on the Timken testing machine. Such test is well known to thoseskilled in the art as being useful in affording valuable informationwith respect to the potential commercial value of extreme pressurelubricants. The Timken machine and test are fully described in theJournal of the Institute of Petroleum 32, pp. 209210 and 220-222 (1946).

The data set forth in Table I were obtained with an acid treated SAE 50grade mineral lubricating oil containing in each instance 5% sulfurizedsperm oil which comprised 10 to 13% sulfur and 3% of a chlorinatedhydrocarbon containing 73% chlorine. The data in Table 2 on the otherhand were obtained on sample also containing varying amounts ofchlorine, sulfur and lead. The latter were also employed in an SAE 50grade oil and tested in the Timken machine.

Table 1.

lreag O1 d gimlren Test ap em 0: esu ts, L d, Run No. thenate (Wt. per-Lbs. 0a

(Wt. percent) cent) Pass Fail 1! 5 None 35 l 5 2 B 4. 2 6. 8 6O 1Commercial basic lead naphthenate (30% Pb).

Table :2

5O Timken Test ResultsLoad, Lbs, With Varying Oleic Percent PercentAcidContents Percent Sulfurized Chlori- Run Pb Naph E.P. nated 1 thenateAgent b E.P. None 2% 4% Agent 55 J I Pass Fail Pass Fail Pass Failggllillfllel'glal basic lead naphthenate7(30% Pb).

urize sperm eontainin 101:0 13 sulfur, exce t wh c Benzyldisulfide (26%s). g 0 p Ere noted d Commercial chlorinated hydrocarbon containing 73%C (OH73- product of Pennsylvania Salt Manufacturing-00.),except whereother- WISBO noted. I m dh ommercia c orinate ydrocarbon eontainin 4042C1 010" fin 42, product of Hercules Powder 00.). g la Whereas thecorrelation of results of the Timken test or any other laboratorytechnique with operational effectiveness is sometimes difficult, it hasbecome apparent that the oleic acid results in improved results in bothlaboratory and operational tests. Actual field testsin the rear axle ofa major automobile manufacturer has demonstrated the outstanding utilityof extreme pressure lubricants containing oleic acid. The manner inwhich the oleic acid contributes to such improvement and the effect thatit hason'the lubricant is not "any understood; However, in addition toits efiectiveness in "increasing load-bearing properties of an extremepressure oil, it 'has been found to contribute to the stability of thelubricant ltself by contributing in large measureto the solubilizationef the variousadditives and particularly'the lead containing soaps.

In connection, howeverfwith the solubilization of the various additivesin an extreme pressure lubricantand particularly the solubilization oflead soaps of various kinds and the other E.P. additives employed, ithas been found that even the use of oleic 'acid does not always resultin completely stable oils from which the additives do not settle outduring storage. And it has been found that certain alkyl phenols" whenemployed relatively minor quantities will enhance thesolubility of thevarious extreme pressure additives, particularly the lead soaps. Thus,monoand dialkyl phenols containing a total of from about 8 to about12"carbon atoms in the alkyl'side chain or chains have been found to beexceptionally effective in maintaining a stable extreme pressurelubricant containing a lead soap with the sulfur and chlorine contamingconstituents. Such alkyl phenols as dibutyl phenol, diamyl phenol,dihexyl phenol, n-octyl phenol, 2-ethyl hexyl phenol, nonyl. phenols,decyl phenols, dodecyl phenols, etc. may be advantageously employed.These phenols may be employed inE.P. oils of the type described inamount of fiom about 1 to about and preferably from about 2 to about 6%;In any event, if two alkyl chains are present, neither preferablycontains less than four carbons.

Set forth in Table 3 are data demonstrating the effectiveness of alkylphenols, both of the monoand dialkyl The data in Table 3 were obtainedfrom certain extreme pressure gear oils, each of which contained, inaddition to the materials set forth in Table 3, 5% sulfurized sperm oil(11% sulfur), 6% chlorinated hydrocarbon 40-42% chlorine), 0.3% dodecylhexasulfide. The oil employed was an acid treated oil having theviscosity of 90 S.S.U. at 210 F. Two to 5 parts per million of asilicone antifoam agent was contained in the oil.

3 Although the specific materials employed int he various tests setforth above were a sulfurized sperm oil and a chlorinated hydrocarbon,it should be understood that many other known sulfur and/ orchlorine-containing materials may be employed in conjunction with thelead soaps of the present invention; Thus, sulfurized hydrocarbons,sulfurized carboxylic acids, e.g. sulfurized tall oil, sulfurized oleicacid, etc., organic sulfides, sulfurized vegetable oils, polysulfides,e.g. the dialkyl tri-, tetra-, pentaand hexasulfides, and otheroil-soluble sulfurcontaining compounds or materials useful in extremepressure lubricants, may be employed in accordance herewith. Referenceis made to US. 2,136,391, 2,202,394, and manyother patents disclosingsulfur-containing additives for extreme pressure addition; suchmaterials are generally useful in accordance herewith. The expressionsjulfur-containing E.P. additive or similar expression is generallydescriptive of these sulfur-containing organic constituents which may beemployed in extreme pressure lubricants. And they, generally, are usefulin accordance herewith in an amount sufiicient to afiord a sulfurcontent. of from about 0.2 to about 3.0% and preferably from about 0.3to about 1.0%. It should be understood that additional amounts of sulfurmay be introduced by the base oil or the solvent extract solubilizer (ifone is type, in maintaining a stable extreme pressure lubricant 1 offrom June to November, when the range of tempera-,

ture variation is. great. -It wil be noted'that a minor amount ofChlorex (B,B'-dichlorodiethylether) extract was employed as anadditional solubilizing agent in two' examples. The presence of such anextract enhances the stability of the oil but its use is usually notnecessary when employing the alkyl'phenol. lubricating oil base stocksmay also 'be employed with advantage; thus, for'example,'extractsresulting from treatment of lubricating oils withfurfural,Chlorex (B,B'-dichlorodiethylether), 50 nitrobenzene, Phenol, cresol,etc. may be employed. These extracts maybe employed, in accordance about1 to 30% and even higher if desired but preferably from about 2 to about10%. Such extracts are obtained in well known processes for solventextraction which need not be described in detail; however, it should benoted that such extracts comprises ordinarily undesirable components oflubricating oils, heater oils, gas oils,

etc., for example, aromatics and/or polynuclear naphthenic compounds.Phenol and Chlorex extracts are preferred for this use.

{In nve-months storage of 4 025 samples during period from June toNovember. H r j are likewise useful.

Other extracts of herewith, in an amount of from employed) but that suchsulfur is not included within the foregoing limits and is ordinarily noteffective for purposes of imparting E.P. properties. I

Chlorinated compounds of various types are employed in extreme pressurelubricants. For example, products obtained by chlorinating paraflin waxor olefinic hydrocarbons have been found to be particularly useful.Individually chlorinated aliphatic compounds such as hexachlorethane,heptachlorpropane, octachlorhutane, etc. Reference'is made to US.2,178,513 which sets forth a substantial number of halogenated 'organicring compounds which are useful inextreme pressure lubricants. Suchmaterials may be employed in accordance with the present invention. US.2,276,341 discloses large numbers of chlorinated hydrocarbons and otherchlorinated organic materials useful in extreme pressure oils. Thesealsomaybe employed in accordance herewith. Chlorine-containing constituentsare employed in extreme pressure lubricants and are useful inaccordanceherewith in anamount sufficient to afford a total chlorinecontent in the lubricant of from about 0.3% to about 8% and preferablyabout 1% to 3%. Materials containing both sulfur and chlorinated'materials, i.e. sulfochlorinated unsaturated compound, particularly ahydrocarbon, may be used. Just as the sulfur containing organicderivatives were referred to above as sulfur containing E.P.,additives'so too will'the chlorine containing materials be referred toas chlorine containing El; additives.

In addition to the sulfurized and chlorinated materials and the leadnaphthenate disclosed hereinabove, it should be understood thatlubricants containing the same may also have added thereto typicallubricating oil additives such as antioxidants, oiliness agents,corrosion inhibitors, detergents, etc. Phosphorus-containing compoundsmay also be employed.- A particularly useful phosphoruscontainingmaterial is that resulting from the treatment of a hydrocarbon, e.g. anolefin polymer, with a phosphorus sulfide. Other phosphorus-containingcompounds, useful in lubricants of this kind, may also be used.

Percentages recited herein and in the appended claims are by Weightunless otherwise indicated.

Having thus described my invention what I claim as novel and desire toprotect by Letters Patent is as follows:

1. An improved extreme pressure lubricant suitable for use under hypoidgear operating pressures comprising a major amount of a minerallubricating oil, an effective amount of lead naphthenate in the range offrom about 1.5% to about an effective amount of a sulfurcontainingorganic extreme pressure agent in the range aifording from about 0.2% toabout 3.0% sulfur, an amount of a chlorine-containing hydrocarbonextreme pressure agent in the range aifording from about 0.3% to about8% chlorine and from about 1% to about 10% of oleic acid.

2. The composition of claim 1 wherein the sulfurcoutaining organicextreme pressure agent is a sulfurized sperm oil.

3. An improved extreme pressure lubricant suitable for use under hypoidgear operating pressures comprising a major amount of a minerallubricating oil, an efiective amount of lead naphthenate in the range offrom about 1.5% to about 10%, an effective amount of a sulfurcontainingorganic extreme pressure agent in the range atfording from about 0.2% toabout 3.0% sulfur, an amount of a chlorine-containing hydrocarbonextreme pressure agent in the range affording from about 0.3% to about8% chlorine, from about 1% to about 10% of oleic acid, and from about 1%to about 10% of an alkyl phenol containing a total of from about 8 toabout 12 carbon atoms in no more than two alkyl side chains, with nosuch side chain containing less than four carbon atoms.

4. The composition of claim 3 wherein the alkyl phenol is nonyl phenol.

5. The composition of claim 3 wherein the alkyl phenol is diamyl phenol.

References Cited in the file of this patent UNITED STATES PATENTS1,319,129 Wells Oct. 21, 1919 2,031,930 Buc Feb. 25, 1936 2,031,986Stratford et a1. Feb. 25, 1936 2,134,554 Grobel Oct. 25, 1938 2,322,209Prutton June 22, 1943 2,367,355 Kaufman et a1. Jan. 16, 1945 2,383,905Zimmer et al. Aug. 28, 1945 2,388,083 Reswick Oct. 30, 1945 2,417,833Lincoln et al Mar. 25, 1947 2,701,237 Sokol Feb. 1, 1955 2,720,491Beretvas Oct. 11, 1955 2,726,209 Fainman Dec. 6, 1955 2,754,269 Wassonet al. July 10, 1956 2,759,893 Beretvas Aug. 21, 1956 OTHER REFERENCESPractical Selection of Improved Lubricants, by Sibley et al., Refinerand Natural Gasoline Manufacture, vol. 14, No. 11, November 1935, page529, Gulf Pub. Co.

1. AN IMPROVED EXTREME PRESSURE LUBRICANT SUITABLE FOR USE UNDER HYPOIDEXTREME PRESSURE LUBRICANT SUITABLE A MAJOR AMOUNT OF A MINERALLUBRICATING OIL, AN EFFECTIVE AMOUNT OF LEAD NAPHTHENATE IN THE RANGE OFFROM ABOUT 1.5% TO ABLUT 10%, AN EFFECTIVE AMOUNT OF A SULFURCONTAININGORGANIC EXTREME PRESSURE AGENT IN THE RANGE AFFORDING FROM ABOUT 0.2% TOABOUT 3.0% SULFUR, AN AMOUNT OF A CHLORINE-CONTAINING BYDROCARBONEXTREME PRESSURE AGENT IN THE RANGE AFFORDING FROM ABOUT 0.3% TO ABOUT8% CHLORINE AND FROM ABOUT 1% TO ABOUT 10% OF OLEIC ACID.